It is known that, on board aircraft, an air conditioning system is provided that feeds the inhabited zones, such as the passenger cabin, the cockpit, and so on, with conditioned air. Such a system takes hot air, and possibly cold air, from the turboshaft engines of the aircraft and converts the air that is taken into conditioned air, distributed in such a zone, then evacuated from the latter to outside the aircraft.
The evacuation to outside the aircraft of the conditioned air is performed with a strong pressure difference, which provokes the creation of a powerful air jet which generates drag for the aircraft.
Furthermore, this pressure difference is representative of an energy that is lost in the evacuation process.
Document U.S. Pat. No. 6,128,896 discloses the general idea of recovering this lost energy and, to this end, addresses the conditioned air evacuated to the turboshaft engines installed on the aircraft.
Moreover, document GB-2 396 208 describes an aircraft including an air conditioning system feeding conditioned air to at least one zone of said aircraft, a zone in which the conditioned air can escape to the outside through an exhaust duct. The aircraft also includes means able to recover, when the aircraft is flying at altitude, the energy of the release of said conditioned air when the latter passes from the conditioned zone to outside the aircraft. The system comprises a switching valve, the sole input of which is positioned in the conditioned zone and of which a first and a second outlets are respectively linked to said exhaust circuit and to said energy recovery means.